fix: resolve strict mode build errors across the codebase

package.json

@@ -60,6 +60,7 @@
     "@types/node": "^24.12.3",
     "@types/react": "^19.2.14",
     "@types/react-dom": "^19.2.3",
+    "@types/three": "^0.185.0",
     "@uiw/react-codemirror": "^4.25.10",
     "@vitejs/plugin-react": "^6.0.1",
     "@vitest/coverage-v8": "^4.1.9",

src/App.tsx

@@ -173,7 +173,7 @@ function App() {
   } as React.CSSProperties
 
   if (bgType === 'color') {
-    containerStyle['--bg-color' as string] = bgColor
+    ;(containerStyle as Record<string, string>)['--bg-color'] = bgColor
     containerStyle.backgroundImage = 'none'
   } else if (bgType === 'image' && bgImage) {
     containerStyle.backgroundImage = `url(${bgImage})`
@@ -211,7 +211,7 @@ function App() {
             const currentNotes = useAppStore.getState().notes
             const idx = currentNotes.findIndex((n) => n.id === noteId)
             if (idx === -1) return
-            const note = currentNotes[idx]
+            const note = currentNotes[idx]!
             const newContent = note.content.slice(0, from) + insert + note.content.slice(to)
 
             window.electronAPI.saveNote(note.id, newContent)

src/GraphView.tsx

@@ -87,7 +87,7 @@ export default function GraphView({
   bgColor,
   accentColor,
 }: GraphViewProps) {
-  const fgRef = useRef<ForceGraphMethods<GraphNode, GraphLink> | undefined>(undefined)
+  const fgRef = useRef<ForceGraphMethods<GraphNode, GraphLink>>(null)
 
   const draggedNodesRef = useRef<Set<string>>(new Set())
   const graphDataRef = useRef<{ nodes: GraphNode[]; links: GraphLink[] }>({ nodes: [], links: [] })
@@ -158,12 +158,12 @@ export default function GraphView({
     const nodes: GraphNode[] = notes.map((n) => {
       const isAuto = /^\d+\.md$/.test(n.id)
       let title = n.id.replace(/\.md$/, '')
-      const folder = n.id.includes('/') ? n.id.split('/')[0] : ''
+      const folder = n.id.includes('/') ? n.id.split('/')[0]! : ''
 
       if (isAuto) {
         title =
           n.content
-            .split('\n')[0]
+            .split('\n')[0]!
             .trim()
             .replace(/^#+\s*/, '') || 'New Note'
       }
@@ -180,22 +180,22 @@ export default function GraphView({
       const reFile = /\]\(\/file\s+([^)]+)\)/g
       let match
       while ((match = reFile.exec(note.content)) !== null) {
-        let targetId = match[1].trim().replace(/\\/g, '/')
+        let targetId = match[1]!.trim().replace(/\\/g, '/')
         if (!targetId.endsWith('.md')) targetId += '.md'
         targets.add(targetId)
       }
 
       const reMd = /\]\(([^)]+\.md)\)/g
       while ((match = reMd.exec(note.content)) !== null) {
-        let targetId = match[1].trim().replace(/\\/g, '/')
+        let targetId = match[1]!.trim().replace(/\\/g, '/')
         if (targetId.startsWith('./')) targetId = targetId.slice(2)
         if (targetId.startsWith('/')) targetId = targetId.slice(1)
         targets.add(targetId)
       }
 
       const reWiki = /\[\[([^\]]+)\]\]/g
       while ((match = reWiki.exec(note.content)) !== null) {
-        let targetId = match[1].split('|')[0].trim().replace(/\\/g, '/')
+        let targetId = match[1]!.split('|')[0]!.trim().replace(/\\/g, '/')
         if (!targetId.endsWith('.md')) targetId += '.md'
         targets.add(targetId)
       }
@@ -299,8 +299,9 @@ export default function GraphView({
   }, [])
 
   const nodeThreeObject = useCallback(
-    (node: GraphNode) => {
-      const color = node.folder ? getFolderColor(node.folder) : accentColor
+    (node: object) => {
+      const gNode = node as GraphNode
+      const color = gNode.folder ? getFolderColor(gNode.folder) : accentColor
       const group = new THREE.Group()
 
       const geometry = new THREE.CircleGeometry(NODE_RADIUS, 32)
@@ -315,9 +316,9 @@ export default function GraphView({
       const ctx = canvas.getContext('2d')!
       ctx.clearRect(0, 0, 256, 64)
       const displayName =
-        node.name.length > MAX_NAME_LENGTH
-          ? node.name.slice(0, MAX_NAME_LENGTH - 3) + '…'
-          : node.name
+        gNode.name.length > MAX_NAME_LENGTH
+          ? gNode.name.slice(0, MAX_NAME_LENGTH - 3) + '…'
+          : gNode.name
       ctx.fillStyle = textColor
       ctx.font = `bold ${LABEL_FONT_SIZE}px sans-serif`
       ctx.textAlign = 'center'
@@ -510,7 +511,7 @@ export default function GraphView({
             }
           >
             <ForceGraph3D
-              ref={fgRef}
+              ref={fgRef as never}
               graphData={graphData}
               numDimensions={2}
               nodeLabel="name"

src/components/KeybindsModal.tsx

@@ -130,11 +130,11 @@ export function KeybindsModal({ onClose }: KeybindsModalProps) {
       if (sc.section === 'global' && sc.action && sc.oldShortcutStorageKey) {
         const oldShortcut = localStorage.getItem(sc.oldShortcutStorageKey) || sc.defaultKey
         if (window.electronAPI.updateGlobalShortcut) {
-          window.electronAPI.updateGlobalShortcut(sc.action, oldShortcut, values[sc.key])
+          window.electronAPI.updateGlobalShortcut(sc.action, oldShortcut, values[sc.key]!)
         }
-        localStorage.setItem(sc.oldShortcutStorageKey, values[sc.key])
+        localStorage.setItem(sc.oldShortcutStorageKey, values[sc.key]!)
       }
-      localStorage.setItem(sc.storageKey, values[sc.key])
+      localStorage.setItem(sc.storageKey, values[sc.key]!)
     }
 
     useAppStore
@@ -175,7 +175,7 @@ export function KeybindsModal({ onClose }: KeybindsModalProps) {
             <KeybindRow
               key={sc.key}
               label={sc.label}
-              value={values[sc.key]}
+              value={values[sc.key]!}
               onChange={(val) => setValues((prev) => ({ ...prev, [sc.key]: val }))}
             />
           ))}
@@ -187,7 +187,7 @@ export function KeybindsModal({ onClose }: KeybindsModalProps) {
             <KeybindRow
               key={sc.key}
               label={sc.label}
-              value={values[sc.key]}
+              value={values[sc.key]!}
               onChange={(val) => setValues((prev) => ({ ...prev, [sc.key]: val }))}
             />
           ))}

src/components/NoteSearch.tsx

@@ -29,7 +29,7 @@ export function NoteSearch() {
   const getNoteTitle = (n: Note) => {
     const isAuto = /^\d+\.md$/.test(n.id)
     const fileName = n.id.replace(/\.md$/, '').split('/').pop() || ''
-    return isAuto ? n.content.split('\n')[0].trim() || 'New Note' : fileName
+    return isAuto ? n.content.split('\n')[0]!.trim() || 'New Note' : fileName
   }
 
   const getNoteTags = (n: Note): string[] => {
@@ -197,7 +197,7 @@ export function NoteSearch() {
             e.preventDefault()
             if (showNoteActionMenu) return
             if (filteredNotes.length > 0) {
-              const selNote = filteredNotes[searchSelectedIndex]
+              const selNote = filteredNotes[searchSelectedIndex]!
               const idx = notes.findIndex((note) => note.id === selNote.id)
               if (idx !== -1) setCurrentNoteIndex(idx)
               setShowNoteSearch(false)
@@ -404,7 +404,7 @@ export function NoteSearch() {
                           width: 8,
                           height: 8,
                           borderRadius: '50%',
-                          backgroundColor: getFolderColor(pathParts[0]),
+                          backgroundColor: getFolderColor(pathParts[0]!),
                         }}
                       />
                       <span className="ns-folder">{pathParts.join(' / ')}</span>

src/components/NoteTitleBar.tsx

@@ -13,8 +13,8 @@ export function NoteTitleBar() {
 
   const isAutoNamed = /^\d+\.md$/.test(activeNote.id)
   const displayTitle = isAutoNamed
-    ? activeNote.content.split('\n')[0].trim() || 'New Note'
-    : activeNote.id.split('/').pop() || ''
+    ? activeNote.content.split('\n')[0]!.trim() || 'New Note'
+    : activeNote.id.split('/').pop()! || ''
 
   const startRename = () => {
     setRenameValue(displayTitle)

src/hooks/useNoteStorage.ts

@@ -28,7 +28,7 @@ export function useNoteStorage() {
   // Save current note index to localStorage
   useEffect(() => {
     if (notes.length > 0 && currentNoteIndex >= 0 && currentNoteIndex < notes.length) {
-      localStorage.setItem('papercache-last-open-note', notes[currentNoteIndex].id)
+      localStorage.setItem('papercache-last-open-note', notes[currentNoteIndex]!.id)
     }
   }, [currentNoteIndex, notes])
 

src/hooks/useReminders.test.ts

@@ -48,14 +48,14 @@ describe('useReminders', () => {
 
     // Should have called the backend to schedule the reminder
     expect(scheduleRemindersMock).toHaveBeenCalledTimes(1)
-    const reminders = scheduleRemindersMock.mock.calls[0][0] as {
+    const reminders = scheduleRemindersMock.mock.calls[0]![0] as {
       key: string
       label: string
       dueAt: number
     }[]
     expect(reminders.length).toBe(1)
-    expect(reminders[0].label).toBe('Buy bread')
-    expect(reminders[0].dueAt).toBeGreaterThan(Date.now())
+    expect(reminders[0]!.label).toBe('Buy bread')
+    expect(reminders[0]!.dueAt).toBeGreaterThan(Date.now())
   })
 
   it('should NOT schedule past-due reminders (already notified by backend on last run)', async () => {
@@ -73,7 +73,7 @@ describe('useReminders', () => {
 
     // Called but with empty array – past reminders are not re-scheduled
     expect(scheduleRemindersMock).toHaveBeenCalledTimes(1)
-    const reminders = scheduleRemindersMock.mock.calls[0][0] as unknown[]
+    const reminders = scheduleRemindersMock.mock.calls[0]![0] as unknown[]
     expect(reminders.length).toBe(0)
   })
 
@@ -90,7 +90,7 @@ describe('useReminders', () => {
 
     renderHook(() => useReminders())
 
-    const reminders = scheduleRemindersMock.mock.calls[0][0] as unknown[]
+    const reminders = scheduleRemindersMock.mock.calls[0]![0] as unknown[]
     expect(reminders.length).toBe(0)
   })
 

src/hooks/useVariables.ts

@@ -17,13 +17,13 @@ export function useVariables() {
       for (const note of notes) {
         let varMatch
         while ((varMatch = reVar.exec(note.content)) !== null) {
-          const name = varMatch[1]
+          const name = varMatch[1]!
           try {
-            globals[name] = evaluate(varMatch[2], globals)
+            globals[name] = evaluate(varMatch[2]!, globals)
           } catch (e) {
             // eslint-disable-next-line no-console
             console.error(`useVariables evaluation error for ${name}:`, e)
-            globals[name] = varMatch[2].trim()
+            globals[name] = varMatch[2]!.trim()
           }
         }
       }

src/lib/editor/MathEvaluator.test.ts

@@ -4,11 +4,11 @@ import { evaluateMath } from './MathEvaluator'
 test('evaluates simple math', () => {
   const changes = evaluateMath('25 * 4 =', {})
   expect(changes.length).toBe(1)
-  expect(changes[0].insert).toBe('\u200B100')
+  expect(changes[0]!.insert).toBe('\u200B100')
 })
 
 test('re-evaluates existing math', () => {
   const changes = evaluateMath('25 * 5 =\u200B100', {})
   expect(changes.length).toBe(1)
-  expect(changes[0].insert).toBe('125')
+  expect(changes[0]!.insert).toBe('125')
 })

src/lib/editor/MathEvaluator.ts

@@ -14,7 +14,7 @@ export function evaluateMath(
   const lines = docStr.split('\n')
   let offset = 0
   for (let i = 0; i < lines.length; i++) {
-    const text = lines[i]
+    const text = lines[i]!
     const lineLen = text.length
 
     if (!text.includes('\u200B') && text.trim().endsWith('=')) {
@@ -49,8 +49,8 @@ export function evaluateMath(
   const reCalc = /^(.*?=\s*)\u200B(.*)$/gm
   let calcMatch
   while ((calcMatch = reCalc.exec(docStr)) !== null) {
-    const exprPart = calcMatch[1]
-    const oldResult = calcMatch[2]
+    const exprPart = calcMatch[1]!
+    const oldResult = calcMatch[2]!
     const fullExpr = exprPart.replace(/=\s*$/, '').trim()
     if (fullExpr) {
       let newResult: string | null = null

src/lib/editor/VariableScope.ts

@@ -28,15 +28,15 @@ export class VariableScope {
       const globalVars = useVariableStore.getState().getGlobals() || {}
 
       while ((varMatch = reVar.exec(docStr)) !== null) {
-        const name = varMatch[1]
+        const name = varMatch[1]!
         try {
           const mergedScope = Object.assign({}, globalVars, newScope)
-          const val = evaluate(varMatch[2], mergedScope)
+          const val = evaluate(varMatch[2]!, mergedScope)
           newScope[name] = val
         } catch (e) {
           // eslint-disable-next-line no-console
           console.error(`VariableScope evaluation error for ${name}:`, e)
-          newScope[name] = varMatch[2].trim()
+          newScope[name] = varMatch[2]!.trim()
         }
 
         const currentNoteScope = useVariableStore.getState().getNoteScope()